diff --git a/include/linux/msi.h b/include/linux/msi.h
index b54010ba7b0d..70cc6a555a8e 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -2,6 +2,20 @@
 #ifndef LINUX_MSI_H
 #define LINUX_MSI_H
 
+/*
+ * This header file contains MSI data structures and functions which are
+ * only relevant for:
+ *	- Interrupt core code
+ *	- PCI/MSI core code
+ *	- MSI interrupt domain implementations
+ *	- IOMMU, low level VFIO, NTB and other justified exceptions
+ *	  dealing with low level MSI details.
+ *
+ * Regular device drivers have no business with any of these functions and
+ * especially storing MSI descriptor pointers in random code is considered
+ * abuse. The only function which is relevant for drivers is msi_get_virq().
+ */
+
 #include <linux/cpumask.h>
 #include <linux/mutex.h>
 #include <linux/list.h>